The paper presents findings from a research study of 318 mathematics teachers' experiences of access to, and use of, digital technology in their professional development in marginalised communities in ten districts across Bangladesh. The innovative two-cycle qualitative study design involved early career researchers collaborating with peer-researcher teachers who interviewed their peers about local teachers' experiences. The interview data was analysed through the lens of Van Dijk's model of digital access and use, addressing motivation, physical access, skills, and usage. The findings reveal that most rural teachers were able to overcome barriers to access and complete the online course using their mobile phones, but the aim of making mathematics learning more active and joyful was only realised among the minority of teachers who had a supportive school environment. Promoting and supporting opportunities for praxis in schools is essential if technology enhanced professional development is to lead to improvements in teaching and learning. The findings have important implications for practice and at policy level to rethink access to professional development through 'mobile first' technologies and support for praxis in schools, in marginalised communities in Bangladesh and elsewhere.